Vaporizer apparatus

ABSTRACT

An electrical heater for liquids, particularly an electrode plate water vaporizer, is proofed against electrical shock hazard by insuring that current paths through the liquid into possible contact with the user are elongated, discontinuous, and on filling when the hazard is greatest, are completely interrupted to assure safety even under negligent handling.

United States Patent References Cited UNITED STATES PATENTS PentzGoodfellow Goodfellow McCloud Lindgren White Blair Black Luse, Jr. et alPrimary Examiner-J. V. Truhe Assistant Examiner-G. R. Peterson Attorney-Davis, Hoxie, Faithful1& l-lapgood ABSTRACT: An electrical heater forliquids, particularly an electrode plate water vaporizer, is proofedagainst electrical shock hazard by insuring that current paths throughthe liquid into possible contact with the user are elongated,discontinuous, and on filling when the hazard is greatest, arecompletely interrupted to assure safety even under negligent handling.

PATENTEDHUV 2 ISTI II III/III I III I III] I A I I I l I I I I I I IImum/0r Robe/H Mum 0/1500 By 00 W5, HOME, Fa/fh/ufl 8 Hapgooo' A from eysY vAronlzait APPARATUS This application is a continuation-in-part of mycopending application Ser. No. 706,809, filed Feb. 20, 1968, entitledApparatus for Applying Air and Vapor to the Face and Hair, now U.S.list. No. 3,495,343.

The present invention is. concerned with apparatus for generating vaporfor such use as a humidifier or vaporizer by raising the temperature ofa liquid such as water or water with added medicaments or the like. Thetemperature of the liquid is raised by electrical means such as anelectrical resistance element or by immersed electrode plates.

Of primary concern in electrically operated vaporizer devices iselectrical shock hazard due to the fact that the liquid to be vaporizedis usually somewhat electrically conductive and may be in directelectrical contact with the electrical power line. This hazard isgreater with immersed electrode plate devices than with resistanceelement devices because the latter are usually electrically insulatedfrom direct contact with the liquid; however, in a moist environment theeffectiveness of the insulation is reduced and commonly allows enoughelectrical current flow to the liquid to'become objectionable. Immersedelectrode plate devices require direct contact between the liquid andthe power line. The hazard is further aggravated at the higher domesticvoltages common in countries foreign to the United States. The hazard isfurther aggravated by the fact that the most common liquid employed iswater and users may be tempted to till the device from electricallygrounded water taps while the device is connected to the power line.Further, the shock hazard with such devices may be greater when theuser's skin is wet.

The vaporizer of the present invention virtually eliminates thepotential shock hazard by maintaining that under all conditions of useand misuse a high resistance path between the electrodes and the user,preventing the user from contacting the liquid in the electrode chamber,and by eliminating any electrical shock consequence from overfilling ortilting of the unit.

In the drawings:

FIG. 1 is an elevational view in section of an embodiment of a vaporizerconstructed in accordance with this invention;

FlG. 2 is a top view of the vaporizer of FIG. 1;

FIG. 3 is a view partly in section taken from the plane 3-3 ofFlG.1;anda FIG. 4 is a view similar to FIG. 1 showing how an attempted erroneousfilling through the vapor exit port is harmlessly discharged.

Referring now to FIGS. 1-3, the apparatus is shown in a preferredembodiment which is in .the form of a room vaporizer for humidifyingroom air or dispensing medicated vapors for sick room use. The apparatuscomprises a housing including a filling receptacle l2 and .a vapor exitport 16. Within the housing 10 is a boiler chamber which can be filledwith the liquid to be vaporized. vaporization is accomplished within theboiler by the well-known technique of passing electrical current througha portion of the liquid between a pair of spaced-electrode plates 22, 23which differ in electrical potential by being connected to the housepower line. The vapor generated by the electrodes collects above theliquid in the boiler chamber 20 and issues from the top wall of theboiler chamber through an opening 24 which is in communication with thevapor exit port 16 of the housing 10. A baffle member 27 helps directthe vapor toward the exit port 16. Liquid to be vaporized is conveyed tothe boiler chamber by means of an inclined ramp, channel, or conduit 26which leads from a point directly below the filling receptacle 12 of thehousing to the opening 24 in the top of the boiler chamber.

Because the liquid to be vaporized is in direct contact with theelectrodes 22, 23 which are at a potential determined by the electricalpower line, it is necessary to isolate the user from direct or indirectcontact with the liquid in the boiler chamber. This is accomplished byproviding very long paths for leakage current from the boiler chamber tothe exterior of the housing; by interrupting, elongating, and reducingthe conductive cross-sectional area of the stream of liquid duringfilling; by insuring that the electrodes are not immersed when the unitis tilted into a draining attitude; and by excluding fingers or probinginstrumentalities from entry or contact with the liquid.

When the surfaces of an electrical device are wet with an uninterruptedfilm of water or other conductive liquid, a conductive path may beestablished between a user in contact with the device and the power lineresulting in risk of electrical shock. The current and voltage dependinversely upon the resistance of the film. This resistance is increasedby increasing the length of the conductive path. Referring to FIGS. 14,the construction of the present device provides only extremely long andconsequently high-resistance paths between a user touching the outsideof the housing and the electrodes on the inside of the enclosed boiler.The boiler chamber 20 is of nonconductive material such as plastic. Theboiler chamber 20 is completely enclosed within the housing 10 which isalso a nonconductor. The boiler chamber 20 is spaced away from theinterior of housing 10 by means of long narrow supporting posts 14. Thisconstruction results in a very long path between the exterior of thehousing 10 and the electrodes on the interior of the boiler chamber 20.All surfaces which may be wetted with condensed vapor are remote fromthe electrodes. Further, the elongated current leakage paths arediscontinuous because the numerous sharp corners in the pathsubstantially reduce the possibility of maintaining an uninterruptedsurface film of liquid. The filmbreaking effect of sharp comers isaugmented by the use of film-breaking sharp edges 21 which discouragethe maintenance of a continuous film current path to the posts 14. Anyconductive path between the electrodes and the housing exterior musttraverse the long narrow support posts 14 which are remote from anyexterior surface. The result of the foregoing characteristics is a lowprobability for an uninterrupted wet surface film conductive path and afilm path resistance in the order of hundreds of thousands of ohms,which is adequate to reduce the current to a harmless level.

To prevent the establishment of a conductive path from the electrodesthrough the body of the user should the user fill the device while it isconnected to the power line, the stream of filling liquid is interruptedand is reduced in cross-sectional area. The filling liquid is pouredinto the funnel-shaped filling receptacle 12. The liquid flows bygravity through one or more small apertures 13 in the bottom of thereceptacle. The size of apertures 13 is chosen to limit the liquid flowto promote the formation of discrete drops rather than a continuousstream. The number of such drop forming apertures is chosen to insurerapid filling. The formation of drops interrupts a conductive path. Thedrops impinge upon an inclined ramp or channel 26 which conveys theliquid to the opening 24 in the top wall of the boiler chamber 20. Theslope of the ramp accelerates the liquid so as to form a relatively thinfilm of moving liquid thereby presenting a minimal cross-sectional areaof liquid for high resistance to current flow. Upon reaching the opening24, the film of liquid is again broken up into discrete drops whichinterrupt any conductive path. The drops fall into the boiler chamber.

Shock hazard risk in the event of overlilling the boiler is reduced byinsuring that the conductive path between the electrodes 22, 23 and thedrain holes 15 is long and of consequent high resistance. Liquid inexcess of the intended capacity of the boiler chamber 20 spills from thevicinity of boiler opening 24 into the space between the boiler chamber20 and the interior of the housing 10. Opening 24 is at a lowerelevation than the top wall of the boiler chamber to form an air lock toentrap a pocket of air to preserve a vapor space in the chamber in theevent of an attempt to overfill. From there it drains out through drainholes 15. Drain holes 15 are located as far from support posts 14 as ispractical to lengthen the path for current between the electrodes 22, 23and the liquid which may spill from drain holes 15.

FIG. 4 shows the vaporizer of the present invention in a tilted positionwhich might be employed to drain the boiler chamber after use of thedevice. In any position, including completely inverted, where liquid canrun out from the boiler chamber, the electrodes are in a position wherethey are no longer immersed. This interrupts any conductive path fromthe electrodes to the draining liquid.

FIG. 4 also illustrates the futility of an attempt to erroneously fillthe boiler chamber through the vapor exit port 16 rather than throughthe intended filling receptacle 12. The liquid simply spills harmlesslyinto the space between the boiler chamber and the housing from which itdrains through the drain holes 15. The erroneously introduced liquid iskept remote from contact with the electrodes.

Fingers and probing instrumentalities are excluded from the boilerchamber by providing opening 245 as the only access to the interior ofthe boiler and by locating opening 24 in a position out of alignmentwith either of the exit port 16 or the filling receptacle 12. Furtherexclusion is provided by covering the vapor exit port 16 with a screenor apertured grid structure 17 with relatively small apertures.

The double shell construction of the present device wherein the boilerchamber is spaced from the housing maintains the exterior of the housingat a comfortably cool temperature while the liquid in the boiler isheated to boiling.

Although the present invention has been described and illustrated withreference to a particular room vaporizer as the preferred embodiment, itis apparent that the invention can be incorporated into variouselectrical liquid heating devices such as central heating systemhumidifiers, food an bottle warmers, sauna devices, etc. Myaforementioned copending application Ser. No. 706,809describes andillustrates incorporation of this invention into a hair dryingapparatus.

I claim:

l. A water heater having a container and spaced electrodes in thecontainer for heating water by passing current from one electrode to theother through the water and in which means for filling the container areprovided comprising a conduit having a downwardly sloping floor with anupper inlet end and terminating in a lower discharge end disposed overan entrance to the container remote from the electrodes, a fillingreceptacle having a drop forming exit orifice positioned above the inletend of the conduit, the arrangement being such that water introduced tothe filling receptacle will flow from its orifice in drops which fall tothe inlet end of the conduit and thence downwardly to fall from thedischarge end of the conduit into the container, whereby discontinuityis imparted to the flow of water to enchance its resistance to thepassage of electrical current therethrough.

2. The water heater as defined in claim 1 in which the downward slope ofthe floor of the conduit accelerates the velocity of flow of water tothereby reduce its average crosssectional area to increase itselectrical resistance.

3. A heater for liquids comprising a nonconductive outer housing, anonconductive liquid heating chamber having a top wall and including anelectrical heater means, said heating chamber being enclosed within theouter housing, said heating chamber being spaced away from the interiorsurfaces of the outer housing by means of elongated electricallynonconductive support members, a filling receptacle for receiving liquidto be conveyed to the heating chamber, said filling receptacle having adrop forming exit orifice, and conduit means leading from a positionbelow the exit orifice to an entrance to the heating chamber, whereby astream of filling liquid is discontinuous to interrupt a flow ofelectrical current therethrough.

4. The heater of claim 3 wherein the conduit is inclined to increase thevelocity of the flowing liquid to decrease its crosssectional area andthereby increase its electrical resistance.

5. The heater of claim 3 wherein the conduit terminates in a positionabove the entrance to the heating chamber to cause the liquid to fallfrom that end of the conduit into the heating chamber in the form ofdrops to further interrupt the flow of electrical current therethrough.

6. The heater of claim 3 wherein the entrance to the heating chamber islocated at an elevation lower than the top wall of the heatin chamber toform within the chamber an air lock whereby t e heating chamber cannotbe completely filled with liquid to preserve a vapor space above theliquid within the heating chamber.

7. The heater of claim 6 wherein the outer housing includes drain holesto discharge liquid which may appear in the space between the heatingchamber and the interior of the outer housing and wherein such drainholes are located remote from the support members to maximize the lengthof a conductive path and its resistance to current flow to the exteriorof the outer housing.

8. The heater of claim 6 wherein the heating chamber is provided withsharp edges and corners to render discontinuous a film of liquid on itsouter surface.

9. A water vaporizer comprising a nonconductive heating chamberincluding an electrode plate water-heating means and a top wall, and anonconductive outer housing including a vapor exit port and a waterfilling receptacle, the heating chamber being spaced away from theinterior surface of the outer housing by elongated support members, theheating chamber having an opening in its top wall for filling and fordischarge of vapor, the vapor exit port being in communication with saidopening, the water-filling receptacle including a drop forming exitorifice, and an inclined channel means for conveying filling waterdownwardly from a position below the drop forming orifice to saidopening whereby the steam of filling water is discontinuous to interruptthe flow of electrical current therethrough.

10. The vaporizer of claim 9 wherein the heating chamber is providedwith sharp edges to interrupt a surface film of water.

11. The vaporizer of claim 9 wherein said opening is at an elevationbelow the maximum interior elevation of the heating chamber to therebypreserve a vapor space above the liquid in the chamber.

12. The vaporizer of claim 9 wherein said opening is at the end of theheating chamber remote from the electrode plate heating means wherebysaid heating means are not immersed when the vaporizer is tipped todrain liquid from the heating chamber through said opening.

13. The vaporizer of claim 9 wherein the vapor exit port and saidopening are not in alignment to exclude instrumentalities from contactwith the water in the heating chamber.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,617,698 Dated November 2, 1971 I t Robert H. Duncanson It is certifiedthat error appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column 1, line 23, cancel "further". Column 4, line 41,

"steam" should read stream Signed and sealed this 29th day of August1972.

(SEAL) Attest EDWARD M. FLETCHER,JR. ROBERT GOTTSCHALK Commissioner ofPatents Attesting Officer FORM PO-1050 (10-69) uscoMM-Dc 60376-P69 U 5VGOVERNMENT PRINTING OFFICE 1969 0-355-334

1. A water heater having a container and spaced electrodes in thecontainer for heating water by passing current from one electrode to theother through the water and in which means for filling the container areprovided comprising a conduit having a downwardly sloping floor with anupper inlet end and terminating in a lower discharge end disposed overan entrance to the container remote frOm the electrodes, a fillingreceptacle having a drop forming exit orifice positioned above the inletend of the conduit, the arrangement being such that water introduced tothe filling receptacle will flow from its orifice in drops which fall tothe inlet end of the conduit and thence downwardly to fall from thedischarge end of the conduit into the container, whereby discontinuityis imparted to the flow of water to enchance its resistance to thepassage of electrical current therethrough.
 2. The water heater asdefined in claim 1 in which the downward slope of the floor of theconduit accelerates the velocity of flow of water to thereby reduce itsaverage cross-sectional area to increase its electrical resistance.
 3. Aheater for liquids comprising a nonconductive outer housing, anonconductive liquid heating chamber having a top wall and including anelectrical heater means, said heating chamber being enclosed within theouter housing, said heating chamber being spaced away from the interiorsurfaces of the outer housing by means of elongated electricallynonconductive support members, a filling receptacle for receiving liquidto be conveyed to the heating chamber, said filling receptacle having adrop forming exit orifice, and conduit means leading from a positionbelow the exit orifice to an entrance to the heating chamber, whereby astream of filling liquid is discontinuous to interrupt a flow ofelectrical current therethrough.
 4. The heater of claim 3 wherein theconduit is inclined to increase the velocity of the flowing liquid todecrease its cross-sectional area and thereby increase its electricalresistance.
 5. The heater of claim 3 wherein the conduit terminates in aposition above the entrance to the heating chamber to cause the liquidto fall from that end of the conduit into the heating chamber in theform of drops to further interrupt the flow of electrical currenttherethrough.
 6. The heater of claim 3 wherein the entrance to theheating chamber is located at an elevation lower than the top wall ofthe heating chamber to form within the chamber an air lock whereby theheating chamber cannot be completely filled with liquid to preserve avapor space above the liquid within the heating chamber.
 7. The heaterof claim 6 wherein the outer housing includes drain holes to dischargeliquid which may appear in the space between the heating chamber and theinterior of the outer housing and wherein such drain holes are locatedremote from the support members to maximize the length of a conductivepath and its resistance to current flow to the exterior of the outerhousing.
 8. The heater of claim 6 wherein the heating chamber isprovided with sharp edges and corners to render discontinuous a film ofliquid on its outer surface.
 9. A water vaporizer comprising anonconductive heating chamber including an electrode plate water-heatingmeans and a top wall, and a nonconductive outer housing including avapor exit port and a water filling receptacle, the heating chamberbeing spaced away from the interior surface of the outer housing byelongated support members, the heating chamber having an opening in itstop wall for filling and for discharge of vapor, the vapor exit portbeing in communication with said opening, the water-filling receptacleincluding a drop forming exit orifice, and an inclined channel means forconveying filling water downwardly from a position below the dropforming orifice to said opening whereby the steam of filling water isdiscontinuous to interrupt the flow of electrical current therethrough.10. The vaporizer of claim 9 wherein the heating chamber is providedwith sharp edges to interrupt a surface film of water.
 11. The vaporizerof claim 9 wherein said opening is at an elevation below the maximuminterior elevation of the heating chamber to thereby preserve a vaporspace above the liquid in the chamber.
 12. The vaporizer of claim 9wherein said opening is at the end of the heating chamber remote fromThe electrode plate heating means whereby said heating means are notimmersed when the vaporizer is tipped to drain liquid from the heatingchamber through said opening.
 13. The vaporizer of claim 9 wherein thevapor exit port and said opening are not in alignment to excludeinstrumentalities from contact with the water in the heating chamber.